Diet in the management of type 2 diabetes: umbrella review of systematic reviews with meta-analyses of randomised controlled trials

Abstract: Objective To systematically summarise and evaluate the existing evidence on the effect of diet on the management of type 2 diabetes and prevention of complications.

Design Umbrella review of systematic reviews with meta-analyses of randomised controlled trials.

Data sources PubMed, Embase, Epistemonikos, and Cochrane, from inception up to 5 June 2022.

Eligibility criteria for selecting studies Systematic reviews with meta-analyses of randomised controlled trials reporting summary effect estimates on the effect of diet on any health outcome in populations with type 2 diabetes were included in the review. Only meta-analyses with randomised controlled trials with the duration of at least 12 weeks were eligible for inclusion. Summary data were extracted by two investigators independently. Summary effect estimates with 95% confidence intervals were recalculated with a random effects model if the information provided was insufficient. Methodological quality was assessed with the A MeaSurement Tool to Assess systematic Reviews (AMSTAR) 2 tool and the certainty of evidence with the Grading of Recommendations Assessment, Development, and Evaluations (GRADE) approach.

Results 88 publications with 312 meta-analyses of randomised controlled trials were included. Methodological quality was high to moderate in 23% and low to very low in 77% of the included publications. A high certainty of evidence was found for the beneficial effects of liquid meal replacement on reducing body weight (mean difference −2.37 kg, 95% confidence interval −3.30 to −1.44; n=9 randomised controlled trials included in the meta-analysis) and body mass index (−0.87, −1.32 to −0.43; n=8 randomised controlled trials), and of a low carbohydrate diet (<26% of total energy) on levels of haemoglobin A1c (−0.47%, −0.60% to −0.34%; n=17 randomised controlled trials) and triglycerides (−0.30 mmol/L, −0.43 to −0.17; n=19 randomised controlled trials). A moderate certainty of evidence was found for the beneficial effects of liquid meal replacement, plant based, Mediterranean, high protein, low glycaemic index, and low carbohydrate diets (<26% total energy) on various cardiometabolic measures. The remaining results had low to very low certainty of evidence.

Conclusions The evidence indicated that diet has a multifaceted role in the management of type 2 diabetes. An energy restricted diet can reduce body weight and improve cardiometabolic health. Beyond energy restriction, dietary approaches such as plant based, Mediterranean, low carbohydrate (<26% total energy), or high protein diets, and a higher intake of omega 3 fatty acids can be beneficial for cardiometabolic health in individuals with type 2 diabetes.

Systematic review registration PROSPERO CRD42021252309.
Data availability statement

Data are available upon reasonable request. All data relevant to the study are included in the article or uploaded as supplementary information. All data are available upon reasonable request. All data for this study were extracted from published meta-analyses, all of which are available and accessible

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: BMJ medicine. - 2, 1 (2023) , e000664, ISSN: 2754-0413

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2023
• Creator: Szczerba, Edyta ; Barbaresko, Janett ; Schiemann, Tim ; Stahl‐Pehe, Anna ; Schwingshackl, Lukas ; Schlesinger, Sabrina

Further information

• DOI: 10.1136/bmjmed-2023-000664
• URN: urn:nbn:de:bsz:25-freidok-2416552
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:56 PM CET